Femoroacetabular Impingement: Surgical Hip Dislocation Approach to the Hip



Femoroacetabular Impingement: Surgical Hip Dislocation Approach to the Hip





The surgical hip dislocation (SHD) approach was described by Ganz and colleagues1 after studying the anatomy of the medial circumflex artery and the blood supply to the femoral head.2 This approach allows complete access to the femoral head and acetabulum and preserves the blood supply and perfusion to the femoral head without the risk of osteonecrosis.3 With the development of hip arthroscopy, indications to perform open surgical treatment to femoroacetabular impingement (FAI) deformities are limited. However, some FAI-related deformities may still be better managed by using the SHD approach, given its versatility and wide exposure to the hip. Patients with anterior-superior cam morphology, with cam deformity located between the 1 and 3 o’ clock position, are usually treated using an arthroscopic approach (Figure 12.1). Our current indications for open treatment of FAI deformity using the SHD approach include the following:



  • Patients lacking internal rotation or with negative internal rotation at 90° of hip flexion.


  • Patients with cam morphology localized posteriorly to the superior aspect of the femoral head-neck junction.


  • Patients with abnormal femoral version, typically femoral retroversion. In addition, those with excessive femoral anteversion may have a specific pattern of acetabular chondral and labral damage and may benefit from open treatment associated with derotational osteotomy.


  • Patients with cam-FAI deformity secondary to moderate and severe slipped capital femoral epiphysis (SCFE) and Perthes disease.


  • Patients with extra-articular FAI, including those with ischiofemoral and greater trochanter impingement.






FIGURE 12.1. Illustration representing the femoral headneck junction regions. Cam deformity localized in the anterior to the anterosuperior region of the femoral head-neck junction can be easily treated by an arthroscopic approach (green area). Cam deformity closer to the superior aspect of the femoral head and neck junction poses more challenge and requires a higher degree of expertise (blue area). When the cam deformity expands posteriorly to the superior aspect of the head-neck junction, arthroscopic resection becomes very difficult (black area). We recommend open treatment using a surgical hip dislocation approach for patients with cam deformity located posterior to the superior aspect of the femoral head-neck junction and for patients with severe restricted motion (those with negative internal rotation with the hip in 90° of flexion).




SURGICAL TECHNIQUE

Surgery is performed under general anesthesia with the patient in the lateral decubitus position with the operated leg resting on a U-shaped pillow (Figure 12.3). A straight lateral incision approximately 20 cm in length is performed slightly anterior to the top of the greater trochanter (Figure 12.4). The subcutaneous tissue is dissected to expose the fascia lata and the gluteal fascia. The anterior border of the gluteus maximus is identified through transparency, and the fascia is divided along the anterior border of the gluteus maximus (Figure 12.5). Dissection is carried out to develop the interval between the gluteus maximus that is retracted posteriorly and the gluteus medius according to the Gibson approach4 (Figure 12.6). The Gibson approach is preferred to the classic Kocher-Langenbeck approach because the former does not violate the gluteus musculature and results in an improved cosmetic result. The fascia lata is opened toward the distal end of the incision. The trochanteric bursa is opened from posterior to anterior, exposing the greater trochanter and the insertion of the gluteus medius and origin of the vastus lateralis (Figure 12.7).







FIGURE 12.3. Illustration showing the patient is in lateral decubitus position with the operated lower extremity placed on top of a U-shaped foam pillow. The entire lower extremity is prepped and draped, allowing visualization of the anterior and the posterior superior iliac spines. A sterile bag drape is placed on the opposite side of the table to receive the leg at the time of the dislocation.






FIGURE 12.4. Intraoperative picture showing a straight incision about 20 cm in length is marked on top of the greater trochanter just anterior to the tip of the trochanter.






FIGURE 12.5. Intraoperative picture showing the exposure of the fascia lata and gluteal fascia. The fascia is opened proximally just anterior to the gluteus maximus musculature (black arrow).






FIGURE 12.6. Intraoperative picture showing the Gibson approach with dissection between the gluteus medius anteriorly and the gluteus maximus posteriorly.






FIGURE 12.7. Intraoperative picture showing the full exposure of the vastus lateralis, greater trochanter, gluteus medius, and gluteus maximus after superficial dissection is undertaken.







FIGURE 12.8. Intraoperative picture showing the gluteus medius that has been retracted anteriorly, exposing the gluteus minimus and the piriformis tendon underneath.

Although the original description by Ganz and colleagues1 recommended that no attempt should be made to mobilize the gluteus medius or to visualize the piriformis tendon, we believe this step is important because it facilitates the correct level of the trochanteric osteotomy and reduces the bleeding at the time of capsular exposure. The gluteus medius insertion on the posterosuperior trochanter is identified and retracted anteriorly to facilitate exposure of the gluteus minimus and the piriformis tendon (Figure 12.8). The piriformis tendon is easily palpated and the fascia on top of it incised to expose the tendon. Internal rotation of the hip facilitates exposure of the piriformis. Careful dissection proximal to the piriformis tendon is recommended to avoid damage to the anastomosis between the inferior gluteal artery system and the deep branch of the medial circumflex artery that usually runs distal to the tendon. The fascia on top of the gluteus minimus tendon is incised after the piriformis tendon is pulled posteriorly. The gluteus minimus is then retracted anterior-superiorly exposing the hip capsule (Figure 12.9). Distally, the posterior fascia of the vastus lateralis is identified and incised longitudinally, leaving about a 3-mm cuff of fascia for later repair. The vastus lateralis is dissected from the femur anteriorly, and a Hohmann retractor is placed under the muscle, avoiding damage to the periosteum (Figure 12.10).

In preparation for the trochanteric osteotomy, an incision is made from the posterosuperior border of the greater trochanter extending distally to the posterior edge of the vastus lateralis (Figure 12.11). There are two ways to perform the trochanteric osteotomy:



  • Classic osteotomy: The classic osteotomy is a straight and single cut. Proximally, it is usually done 2 to 3 mm anterior to the insertion of the gluteus medius and distally at the posterior aspect of the origin of the vastus lateralis. The oscillating saw is used up to the medial cortex, which should be completely cut with an osteotome. The original technique describes a trochanteric fragment of about 1.5 cm. Having exposed the piriformis tendon previous to the cut allows for the safe performance of a thicker cut without the risk of leaving the piriformis in the mobile trochanter fragment. This technique is preferred when planning for a dissection of the retinacular flap and distal transfer of the greater trochanter (ie, SCFE and Perthes hips).


  • Step-cut osteotomy: In this technique, the proximal part of the osteotomy is more superficial, whereas the distal portion of the osteotomy is slightly deeper (more medial). The two cuts are then connected by a third transverse cut done with an osteotome, creating a step in the osteotomy of at least 6 mm. The step-cut osteotomy has the advantage of improving the area of contact of the osteotomy and avoiding rotation or proximal migration of the trochanter fragment (Figure 12.12).






FIGURE 12.9. Intraoperative picture showing the dissection of the interval between the gluteus minimus and the piriformis tendon. A, The piriformis tendon is grasped with forceps and pulled posteriorly, exposing the gluteus minimus insertion in the hip capsule. B, The gluteus minimus fascia is opened, and the muscle is dissected out of the capsule and the posterior ilium to the level of the greater sciatic notch.

The trochanteric piece is flipped and mobilized anteriorly with the attached vastus lateralis and gluteus medius. Posteriorly, the previously exposed gluteus minimus is
further completely elevated anteriorly off the hip capsule. The gluteus minimus should be released posteriorly as far as the level of the sciatic notch—this will avoid difficulty with acetabular exposure. Distally, the anterolateral portion of the vastus lateralis is released from the femur along with the insertion of the vastus intermedius, which is facilitated by flexion, abduction, and external rotation of the hip. The hip capsule is completely exposed from the anterior to the posterosuperior aspect (Figure 12.13). With complete exposure of the capsule, a capsulotomy is performed in a Z shape fashion (right hip) or reverse Z shape (left hip). The capsule is cut initially in line with the longitudinal axis of the anterior neck, starting at the superoanterior corner of the trochanteric osteotomy. The longitudinal flap is only partially opened. The distal capsulotomy extends anterior toward the anteroinferior aspect of the acetabulum. Finishing the distal anteroinferior flap allows for safe completion of the longitudinal flap to the level of the acetabular labrum. At the level of the labrum, the capsular opening is curved posteriorly parallel
to the acetabular rim and toward the piriformis tendon. With the capsule opened, the joint is inspected for signs of synovitis and for dynamic assessment of range of motion with special attention to flexion and internal rotation. Intra- and extra-articular causes of FAI can be dynamically determined (Figure 12.14). Flexion, adduction, and external rotation allow for subluxation of the hip. Further resection of the ligamentum teres allows a complete dislocation of the femoral head. Once the femoral head is dislocated from the acetabulum, the leg is placed in a sterile bag on the opposite side of the table (Figure 12.15).

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May 10, 2021 | Posted by in ORTHOPEDIC | Comments Off on Femoroacetabular Impingement: Surgical Hip Dislocation Approach to the Hip
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